Vancouver's Private Residences at Hotel Georgia (Rosewood Hotel Georgia) took about a year to complete excavating 50 m deep (according to info provided from the link) for its foundation (deepest excavation in Vancouver, due to the small footprint size of the 48-floors project, to accommodate all of the hotel/residences/business office parking) and constructing an 8 level underground garage structure from about 2008 to 2009. According to posts on "The Georgia" section in this SSP forum, excavation took about 6 or 7 months -- from about Apr/2008 to Sep/2008 -- and reached grade by May/2009. PRHG was essentially complete 3 years later.
I imagine CP will be digging deeper than 50 ft (15 m) for its foundation, maybe not as deep proportionally to the HG project. I don't know how much the differences in foundation construction between each project would affect CP's timeline, as HG's foundation is probably anchored differently than CP's. But CP's foundation is significantly shallower than HG's so hopefully they can complete CP up to ground level within the year, and start building above ground soon after that!